Snow making apparatus and method

ABSTRACT

A snow making apparatus that allows for the production of snow when the outdoor air temperature is from about −3° Celsius or colder to about +5° Celsius. The snow making apparatus includes a snow machine that includes one or more water nozzles that spray a water mist into the air. The snow making apparatus also includes a snow accelerator that includes an air compressor, a dehumidifier to remove moisture from the compressed air and a cooling system to cool the compressed dehumidified air. The cooled air is passed through an expansion valve and the modified compressed air is directed through a nozzle positioned to lie near the water nozzles. The modified compressed air has a absolute humidity of about 0.02 g/m 3  or less and a temperature of about −50° Celsius or less. The water mist and modified compressed air are combined, causing the water mist to turn into snow.

BACKGROUND

The present disclosure relates to machines, and particularly to snowmachines used to make snow. More particularly, the present disclosurerelates to a snow machine that produces snow at higher atmospherictemperatures. In order for a ski resort to attract skiers, sufficientsnow must be provided on the slopes for skiing. The longer the skiresort can maintain a snow base on the slopes, the longer the ski resortcan operate.

In traditional ski resorts, artificial snow has been produced using snowmachines when sufficient snow can not be obtained under naturalconditions. The snow machines mix water, which is cooled to about −3°Celsius, with compressed air and the mixture is blown from nozzles intothe air. The compressed air and water mixture turns into snow before thewater droplets reach the ground. Atomized water droplets from thenozzles of the snow machine can produce a large amount of snow quicklyusing the evaporation heat from the water due to the frigid air.

Snow production becomes difficult or impossible when the outside airtemperature is from about −3° C. to about 0° C. and above, because thecrystallization speed of the water droplets is slow due to the higheratmospheric temperatures. Several snow making methods have been proposedfor producing snow. Japanese patent application H08-110137 teaches theuse liquid nitrogen to make snow crystals. The cost of using liquidnitrogen is high and this technique has not been commercialized.Japanese patent applications JP2001-201221, H10-339532, H03-501404, andH11-172940 teach snow surface maintenance methods that use dry air.However, these methods are used to form snow crystals naturally inenclosed spaces, and include the method of controlling the temperatureand humidity in an enclosed space. These methods are not designed to beused outdoors.

Japanese patent application H10-339532 teaches a method used to maintainthe humidity and temperature in enclosed spaces and a method used tosecure the height when water mist is sprayed and changed into the snowaccording to the time of mist falling. Again, this system is notdesigned to be used outdoors.

Japanese patent application JP2001-304732 teaches the method of outdoorsnow making and requires the air to have a temperature of 0° C. or lessand the dew point 0° C. or less. However, according to this condition,the relative humidity is 100% and water evaporation can not be utilized.Artificial snow making can not be expected using this method.

Hence, according to the description of JP2001-304732, the temperaturenear the upper limit of the air to be acted on is not clear. Actually,as to snow making enabling conditions, outside air conditions have toppriority, and is the main factor for snow making. Unless the wet bulbtemperature is 0° C. or less, even snow that fell naturally would melt.In reverse, unless the temperature is less than 0° C., water dropletswould not make snow naturally.

Japanese Patent application JP06-257917 teaches directly injecting intotwo fluid nozzles on the air side of the snow machine. In this case,right before spouting from the fluid nozzles, the air mixes with waterand the cold energy of the air is absorbed into the water. Hence, theadvantage of low temperature and low humidity air can not be utilized atall.

In recent years, it is rare to find a ski resort in Japan that has anoutside temperature of −3° C. or less in February. During this periodthe snow machines are inoperable and it is not possible to obtain snowaccumulation of sufficient volume for skiing. In order to solve thisproblem, in recent years, even if the outdoor temperature is high, snowmaking is done using the ice making machine that can produce snow.However, when ice making machines are used, power consumption is largereducing resort profits.

SUMMARY

According to the present disclosure, a snow machine includes a watersupply and one or more nozzles that are used to create water dropletsused to make snow when the outside temperature is not only 0° C. orless, but also up to +5° C.

In illustrative embodiments, the snow making machine includes a snowaccelerator that is provided with an air compressor for compressing air,and equipment that adsorbs moisture from the compressed air. The snowaccelerator also includes cooling equipment which cools the low humidityair. The snow accelerator further includes an air expansion valve thatsubjects the compressed air to decompression expansion and an air nozzlethat discharges the modified compressed air from the air expansion valveinto the atmosphere adjacent a water jet nozzle of the snow machine. Thesnow system is controlled by a control device. The modified compressedair, which has an absolute humidity of about 0.1 grams per cubic meter(g/m3) or less and a temperature of about −20° C. or less, is ejectedfrom a spray nozzle against the water mist being sprayed from the waternozzles of the snow machine to cause the water mist to change into snowice crystals, making snow.

Additional features of the disclosure will become apparent to thoseskilled in the art upon consideration of the following detaileddescription of illustrative embodiments exemplifying the best mode ofcarrying out the disclosure as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1A is a flow diagram showing the entire structure of a gun typesnow machine;

FIG. 1B is a elevational view of the snow nozzle of FIG. 1A showing ahigh pressure water inlet and a high pressure air inlet;

FIG. 2 is an flow diagram showing a snow accelerator combined with a guntype snow machine;

FIG. 3A is a side elevational view showing the snow accelerator nozzlecombined with a gun type snow machine;

FIG. 3B is a front elevational view of the snow accelerator nozzlecombined with the water nozzle of the snow machine;

FIG. 4 is an elevational view showing the snow accelerator nozzle addedto a fan-type snow machine;

FIG. 5 is a flow diagram of the snow accelerator; and

FIG. 6 is flow diagram of a separation type of a snow accelerator.

DETAILED DESCRIPTION

A snow accelerator machine 100 is shown coupled to snow machine in theillustrative embodiment of FIG. 2. The present disclosure offers amethod and apparatus in which water vapor is evaporated from spray waterdroplets, cooled and crystallized by use of low temperature air. Theconditioned air has a very low temperature and an extremely lowhumidity. In terms of numeric values, the conditioned air has atemperature of about −40° C., absolute humidity of about 0.02 g/m3, andthe frost point temperature of about −55° C. or less.

The air adjusted by the disclosed method will be hereinafter calledmodified air. FIG. 1A shows a snow gun 102 which is a type of a snowmachine 13. The snow gun 102 includes a plurality of nozzles 11 thatspray water droplets to form a mist. Nozzles 11 are coupled to a highpressure air supply line 12 and a high pressure water supply line 13.Air and water from the supply lines 12, 13 spout from the nozzles 11 ofthe snow gun 102. By using snow accelerator 100 and spraying themodified air from nozzles 34, atomized water droplets are frozen at afaster rate, and snow crystals and ice crystals are produced.

The compressed air used for snow making by a snow machine 104 isproduced by the following method. An air compressor 1 takes in the airfrom an air intake 2. In this example, the atmospheric air has arelative humidity of 80%, a temperature of 0° C., and an absolutehumidity 3.89 g/m3. When the air is compressed from its suctiontemperature around 0° C. and 0.7 Mpa, the air temperature climbs toabout 30° C. The temperature of the compressed air at this stage is toohigh, and it is not likely to assist in making snow.

Thus, the air leaving air compressor 1 is cooled to the temperature ofabout +5° C. by cooling device 4. At this temperature the moisture inthe air is not frozen by cooling device 4. Water separation filter 3discharges the saturated water from the compressed air. The dischargedair goes through the high pressure air line 12 from a flange 5 and isconnected to the air connection 9 of snow gun 102, as shown in FIG. 1B.

Water used by the snow gun 102 is stored in a storage tank 6 or issupplied by city water lines, as shown, for example, in FIG. 1A. Thewater exits storage tank 6 and passes through filter 7. Filtered wateris pressurized to about 1.5 Mpa by a water pump 8, and passes throughhigh pressure water hose 13. High pressure water hose 13 is connected towater connection 10 of nozzle 104. Snow making by a traditional snowmachines is done using the method described so far. However, if theoutside temperature increased to −3° C. or greater, snow making is notpossible.

Snow accelerator 100 is added to snow gun 102 and is used to enhance thesnow making abilities of snow gun 102 when less than ideal weatherconditions exist (−3° C. or greater), as shown in FIGS. 2 and 5. Snowaccelerator 100 includes an air dehumidifier 54 that comprises twovessels 54(a), 54(b). The first vessel 54(a) adsorbs moisture to dry theair, and the second vessel 54(b) performs the drying process in theevent the first vessel 54(a) is offline. Valving is used to selectivecontrol the airflow through the vessels 54(a) and 54(b). The airdehumidifier 54 uses moisture absorbent zeolite 56 to absorb themoisture from the air. While zeolite is preferred, other multi-porousmoisture absorbent materials can also be used including active alumina,silica gel, molecular sieves, active carbon, which all act asabsorbents.

When the pressurized air is dehumidified using this method, the absolutehumidity at the frost point temperature is about 0.1 g/m3 at about −40°C. If the temperature is higher than −40° C., frost is not generated inthe air stream or related conduits. Thus, if the air is cooled by afreezer 62 to −30° C., frost or ice is not generated inside the airpassages.

Air at tee 20 of FIG. 2 passes from a coupler 50 through a dust filter67, a drain water filter 51, and a check valve 52, as shown in FIG. 5.Air passing through check valve 52 passes through a four way valve 53,and then passes through the first dehumidifying tank 54(a) equipped withzeolite 56. The air exiting dehumidified tank 54 it is dehumidified.Dehumidified tanks 54(a) and 54(b) repeat the dehumidifying process andrenewal process alternatively so that one of the two systems is alwayson line. In general, 15% of dry air created by the dehumidifier tanks isused for renewal. The dehumidified air used for renewal is dischargedfrom a discharge coupler 66, as shown in FIG. 5.

The dehumidified air passes through a check valve 52 and a filter 57,and is cooled inside the air exchanging device 59, as shown in FIG. 5.With regard to the method used for cooling the dehumidified air, thecooling medium that was sent out from the freezer 62 is subjected to athrottle expansion by the expansion valve 58. Air from the air expansionvalve 58 enters cooling duct coil 60, and is cooled to an evaporationtemperature from about −35° C. to about −40° C. Heat exchanged coolingmedium returns and passes through duct 61 and returns to a freezer 62,to form a cooling cycle.

The cooling method used is a general cooling method. Hence, no detailsare particularly described about the cooling equipment, cooling mediumand the like. The cooling system used is required to reach a temperaturefrom about −35° C. to about −40° C. to sufficiently cool thedehumidified air. Here, the dry air from the dehumidifier was cooled to−30° C. which is higher than the frost point temperature and forms themodified or adjusted air for accelerating the production of snow.

If the incoming air volume from the compression air inlet 50 is largerthan the capacity of the adsorption dehumidifier 54, then the desiredspecified dehumidification is not obtained. Hence in order to adjust forthis condition a user, after looking at the indicator value of the airmeter 65, adjusts the flow volume of the compressed air by use of an airexpansion valve 63, as shown, for example, in FIG. 5. Air expansionvalve 63 allows a user to attain the specified air volume. By makingthese adjustments, the air under pressure expands in volume, and causesdehumidification and the temperature to drop.

In conducting tests, the test snow making machines were run for 8 hourswith modified compressed air having an absolute humidity of about 0.1g/m3 at about −40° C. After running the equipment for eight hours it wasconfirmed that no frosting was generated in the flow route of thecooling air, and no blocking of the lines was generated. FIG. 3A showsthe conditions in which a snow accelerator 100 is added to the snowmachine 104 that is run in the condition in FIG. 1A. The air nozzleequipment 33, 34 is coupled to the snow gun 31 by use of mounted stay32. The modified compressed air is sprayed from nozzles 34. However, anadiabatic expansion is not performed by these nozzles.

Ring shaped adjusted air supply duct 33 is fitted with spout nozzles 34,which are arranged in a radial pattern. As to the nozzle design, sprayangles and fan width of the spray should be taken into account so thatmaximum contact is made with the spray water. Modified compressed air iscoupled to air supply duct by use of connector 30.

During the test, spray water 14 was sprayed from the snow gun 31 underhigh pressure, and the adjusted air 35 exiting the nozzles 34 wassubjected to an adiabatic expansion and surrounded the spray water 14,as shown, for example, in FIG. 3A. Modified compressed air 35 exitingthe nozzles 34 had a reduction of moisture by 1/7. The absolute humidityof the air exiting the nozzles 34 became 0.014 g/m3 and the temperaturewas −60° C. at the nozzle outlet.

If one observes the spout 14 of the snow machine, as the water spray 14moves forward, the air layers of the modified compressed air 35 and thespray flow 14 get mixed. Placing a hand about 5 to 6 meters in front ofthe snow machine during the test, it was confirmed that the waterdroplets were changed into about 1 mm ice particles. The structure of afan-type snow machine is illustrated in FIG. 4.

In a fan-type snow machine, a fan 44 is placed inside the cylindershaped wind channel housing 48, and air is blown forward through thewind channel housing 48 by fan blade 44, similar to a hair drier. Inthis illustration, shaft 46 of fan 44 is rotated by a motor and drivebelt or is powered by a hydraulic motor. As to its structure, apressurized water duct 49 positioned in a ring shape is positioned infront of the wind channel housing 48. Water is ejected from a pluralityof nozzles 40 into the air passing from the wind channel housing 48. Thefeed water supply from pressurized water pump 8 is connected to hose 42to feed the nozzles similar to the method shown in FIG. 1A.

The modified compressed air supply 64 of FIG. 5 made by the snowaccelerator 108 is connected to line 47(a), as shown in FIG. 4. Modifiedcompressed air exits nozzle 47 and is blown into the suction 45 createdby fan blade 44. The dehumidified low temperature air does not causefrost on the fan 44 or the internal wind channel 48, and, duringtesting, continuous snow making acceleration effect was obtained.

The run conditions at the time of testing were as follows; inlet waterpressure was approximately 1.5 Mpa, water volume was about 200 L/min,outside air temperature was about +3.6° C., wet bulb temperature wasabout −2.1° C., and relative humidity was about 18.5% RH. The modifiedair from nozzle 47 was blown inside of the wind channel 48. Modified aircontacted the misty water that was ejected from nozzles 40 of thepressurized water duct 49 and the entire volume of water was convertedinto snow.

It is difficult to visually measure at what distance from the windchannel outlet, the snow was formed, and however it can be confirmedthat snow was formed by the snow fall on the ground. When the modifiedair supply from nozzle 47 stopped, the water from nozzles 40 immediatelychanged to misty rain.

A large ski resort is equipped with a snow making system, as shown, forexample, in FIG. 1A-1B. The system includes an air compressor 1, watersupply equipment having a pressurized pump 8 and a nozzle 11. During thetest, the snow accelerator 100 was added to existing snow makingequipment and it was found that by using the snow accelerator 100, snowcould be made in conditions where snow making was not previouslypossible.

The snow making test was started under the following conditions: outsidetemperature +3.6° C., wet bulb temperature −2.1° C., and humidity 18.5%RH. The test snow gun arrangement with the snow accelerator that wasused during the test is shown in FIG. 2. FIG. 2 shows the combination ofthe nozzles that spout the modified air to the snow gun. The aircompressor 1 was pressurizing air to a pressure of about 0.7 Mpa and aflow rate of about 17 m3/min and the water pump 8 pressurized the waterto pressure of about 1.3 Mpa with a flow rate of about 200 L/min, and atemperature of about +3.5° C. Connection hose 13 from the pump wasconnected to the snow gun 11 at connection 10 and the facility was run.

Under these test conditions, initially, when the sprayed misty waterdropped to the ground about 8˜15 meters in front of the machine, mistyrain was produced but turned to snow. When this condition prevailed, themodified air had a temperature of about −32° C., absolute humidity ofabout 0.1 g/m3 and a frost point temperature −45° C. was made by thesnow making acceleration machine of FIG. 5. The air supply pressure wasadjusted by air expansion valve 63. The main part of the expansion valve63 is the needle valve, which is used to control the rate of air throughthe valve.

At this time in the test, air temperature was −60° C. or less at theoutlet of the expansion valve 63 and the absolute humidity dropped to0.014 g/m3. FIG. 3 is the expanded detail of Part M of FIG. 2 with themodified air coupled to connection 9 of the gun and the water supplycoupled to connection 10. The adjusted air passes through the air ring33 having a plurality of nozzles 34 attached thereto. Nozzle positionsare adjusted so that collision of the modified air occurs with the spraywater.

Almost at the same time as spraying water from the nozzles, it wasconfirmed that the water droplets were changing into snow within a fewmeters of the fan outlet. Even during this snow making, the naturaloutdoor conditions kept changing all the time. Even after six hours hadpassed and the air temperature climbed to +3.5° C. and the wet bulbtemperature was −1.2° C., snow making continued. The change to snowdecreased in the vicinity of an outside temperature of +4.3° C. and awet bulb temperature of 0° C. Under these conditions, the water volumewas decreased and an adjustment was made. In this test, by making an airadjustment, the snow making in the +0° C. temperature area wasrecognized to occur. And during test runs, no blocking or frostingoccurred in any of the supply lines.

As a comparison example, the adjusted air of temperature 40° C.,absolute humidity 0.1 g/m3, frost point temperature −45° C. from the airproduced by the snow accelerator in FIG. 5 was connected directly to thesnow gun air coupling 9 in FIG. 1 from a coupler 64, and snow making runwas attempted. The test was run to see what kind of effects would beproduced compared with the first and second tests. As a result, when themachine was run at the outside air −2° C., no crystallization was seenin the misty water.

As part of the test, the adjusted/modified air was directly connected tothe air connector 9 of the snow gun main body 11, and mixed with thewater within the gun, the cold energy in the air is absorbed into thewater as a latent heat. This arrangement did not contribute to improvingthe snow making capability of the snow machine. It was understood fromthe test that the water temperature exiting the nozzles dropped alittle.

FIG. 6 shows an example of a separation type snow accelerator 100 forlong distance use. The snow accelerator 100 of FIG. 5 shows a separationline 68 that has the air dehumidifier on the right side of the figure,and the air cooling equipment on the left side of the figure. In FIG. 6,one air dehumidifier 70 is used for a plural number of cooling systems71.

Using a large air dehumidifier 70 for multiple cooling systems 71 allowsfor the air dehumidifier to be installed at the lower part of the skislope. The cooling systems 71 can be positioned at 500 meters and 600meters on top of the mountain, for example, near the snow machine mainbody. With this arrangement a plural number of the air cooling devices71 can be installed near the snow machine main body. Placing the coolingdevices 71 at the site of the snow machine reduces the size of thecooling equipment needed, decreasing individual equipment costs andconstruction costs.

Minimalizing the equipment size simplifies the installation work of theequipment, which is greatly desired. If the dehumidification process ofthe dehumidifier is positioned at the foot of the mountain, the ductline 72 does not freeze because the air passing through the line isdehumidified. Since the equipment is used in the winter time, a longerthe duct line 72 is beneficial because the line is cooled by the outsideconditions, requiring a smaller cooling device 71.

While this invention has been described as having a preferred design,the present invention can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

1. A method for making snow in a non-sheltered outdoor environment wherethe outdoor air temperature is from about −3° Celsius to about +5°Celsius and has a wet bulb temperature of no more than about 0° Celsius,the method comprising the steps of: ejecting pressurized water through afirst nozzle to produce water droplets; producing conditioned compressedair that has an absolute humidity of no more than about 0.1 g/m³ and atemperature of no more than about −20° Celsius; passing the conditionedcompressed air through an air expansion valve to form modifiedcompressed air having an absolute humidity of no more than about 0.02g/m³ and a temperature of no more than about −50° Celsius; ejecting themodified compressed air from a second nozzle that is positioned to lienear the first nozzle; wherein the water droplets ejected from the firstnozzle encounter the modified compressed air ejected from the secondnozzle and turn into ice crystals to form snow.
 2. The method for makingsnow of claim 1, wherein the conditioned compressed air is formed by useof an air compressor to pressurize the air and a dehumidifier system toremove moisture from the pressurized air.
 3. The method for making snowof claim 2, wherein the dehumidifier system uses multi-porous moistureabsorbent materials to dehumidify the pressurized air.
 4. The method formaking snow of claim 2, wherein the dehumidifier system uses twoindependent dehumidifiers and valving to allow for selective control ofthe pressurized air through the dehumidifiers.
 5. The method for makingsnow of claim 4, wherein the conditioned compressed air is cooled by useof a cooling system.
 6. The method for making snow of claim 5, whereinthe compressor and dehumidifier system are positioned to lie near thecooling system.
 7. The method for making snow of claim 5, wherein thecompressor and dehumidifier system are separated from the coolingsystem.
 8. The method for making snow of claim 7, wherein the coolingsystem is positioned to lie near the point where the snow is producedand is in fluid communication with the air compressor and dehumidifiersystem.
 9. A snow making machine that can produce snow when the outdoorair temperature is from about −3° Celsius to about +5° Celsius and has awet bulb temperature of no more than about 0° Celsius, the snow makingmachine comprising: a pressurized water supply; at least one waternozzle coupled to the pressurized water supply, the water nozzle adaptedto spray water in fine droplets to form a mist; a snow acceleratorcomprising an air compressor for compressing air; a dehumidifier systemfor dehumidifying the air compressed by the air compressor; a coolingsystem for cooling the air dehumidified by the dehumidifier system; anair nozzle that is adapted to expel air that has been modified by theair compressor, dehumidifier system and cooling system, the air nozzlepositioned to lie near the water supply nozzle to allow the modified airto mix with the mist to form snow.
 10. The snow making machine of claim9, wherein the snow accelerator includes an expansion valve forexpanding the air cooled by the cooling system.
 11. The snow makingmachine of claim 9, wherein the air exiting the air nozzle has anabsolute humidity of no more than about 0.02 g/m³ and a temperature ofno more than about −50° Celsius.
 12. The snow making machine of claim 9,wherein the dehumidifier system uses multi-porous moisture absorbentmaterials to dehumidify the pressurized air.
 13. The snow making machineof claim 12, wherein the dehumidifier system uses two independentdehumidifiers and valving to allow for selective control of thepressurized air through the dehumidifiers.
 14. The snow making machineof claim 9, further including a fan blade to create moving air.
 15. Thesnow making machine of claim 14, wherein the fan blade is positionedbetween the water nozzle and the air nozzle.
 16. The snow making machineof claim 14, wherein the fan blade is positioned to lie near the waternozzle.
 17. The snow making machine of claim 16, further including ahousing, wherein the fan blade is positioned within the housing.
 18. Thesnow making machine of claim 9, wherein the snow making machine includesa plurality of water nozzles coupled to a water manifold.
 19. A snowmaking machine that can produce snow when the outdoor air temperature isfrom about −3° Celsius to about +5° Celsius and has a wet bulbtemperature of about 0° Celsius or less, the snow making machinecomprising: a pressurized water supply; a tubular housing; a fanpositioned within the tubular housing and adapted to create a flow ofair through the tubular housing; a plurality of water nozzle coupled tothe pressurized water supply, the water nozzles positioned around thediameter of the tubular housing and adapted to spray water in finedroplets to form a mist; an air compressor for compressing air; adehumidifier system for dehumidifying the air compressed by the aircompressor; a cooling system for cooling the air dehumidified by thedehumidifier system; an air nozzle that is adapted to expel air that hasbeen modified by the air compressor, dehumidifier system and coolingsystem, the air nozzle positioned to lie near the water supply nozzlesto allow the modified air to mix with the mist to form snow.
 20. Thesnow making machine of claim 19, wherein the air exiting the air nozzlehas an absolute humidity of about 0.02 g/m³ or less and a temperature ofabout −50° Celsius or less.